/*
 * SHA-512 algorithm as described at
 *
 *   http://csrc.nist.gov/cryptval/shs.html
 *
 * Modifications made for SHA-384 also
 */

#include "ssh.h"

#define BLKSIZE 128

/*
 * Arithmetic implementations. Note that AND, XOR and NOT can
 * overlap destination with one source, but the others can't.
 */
#define add(r, x, y)                                                           \
  (r.lo = y.lo + x.lo, r.hi = y.hi + x.hi + ((uint32)r.lo < (uint32)y.lo))
#define rorB(r, x, y)                                                          \
  (r.lo = ((uint32)x.hi >> ((y)-32)) | ((uint32)x.lo << (64 - (y))),           \
   r.hi = ((uint32)x.lo >> ((y)-32)) | ((uint32)x.hi << (64 - (y))))
#define rorL(r, x, y)                                                          \
  (r.lo = ((uint32)x.lo >> (y)) | ((uint32)x.hi << (32 - (y))),                \
   r.hi = ((uint32)x.hi >> (y)) | ((uint32)x.lo << (32 - (y))))
#define shrB(r, x, y) (r.lo = (uint32)x.hi >> ((y)-32), r.hi = 0)
#define shrL(r, x, y)                                                          \
  (r.lo = ((uint32)x.lo >> (y)) | ((uint32)x.hi << (32 - (y))),                \
   r.hi = (uint32)x.hi >> (y))
// clang-format off
#define and(r,x,y) ( r.lo = x.lo & y.lo, r.hi = x.hi & y.hi )
#define xor(r,x,y) ( r.lo = x.lo ^ y.lo, r.hi = x.hi ^ y.hi )
// clang-format on
#define not(r, x)(r.lo = ~x.lo, r.hi = ~x.hi)
#define INIT(h, l)                                                             \
  {                                                                            \
    h, l                                                                       \
  }
#define BUILD(r, h, l) (r.hi = h, r.lo = l)
#define EXTRACT(h, l, r) (h = r.hi, l = r.lo)

/* ----------------------------------------------------------------------
 * Core SHA512 algorithm: processes 16-doubleword blocks into a
 * message digest.
 */

#define Ch(r, t, x, y, z) (not(t, x), and(r, t, z), and(t, x, y), xor(r, r, t))
#define Maj(r, t, x, y, z)                                                     \
  (and(r, x, y), and(t, x, z), xor(r, r, t), and(t, y, z), xor(r, r, t))
#define bigsigma0(r, t, x)                                                     \
  (rorL(r, x, 28), rorB(t, x, 34), xor(r, r, t), rorB(t, x, 39), xor(r, r, t))
#define bigsigma1(r, t, x)                                                     \
  (rorL(r, x, 14), rorL(t, x, 18), xor(r, r, t), rorB(t, x, 41), xor(r, r, t))
#define smallsigma0(r, t, x)                                                   \
  (rorL(r, x, 1), rorL(t, x, 8), xor(r, r, t), shrL(t, x, 7), xor(r, r, t))
#define smallsigma1(r, t, x)                                                   \
  (rorL(r, x, 19), rorB(t, x, 61), xor(r, r, t), shrL(t, x, 6), xor(r, r, t))

static void SHA512_Core_Init(SHA512_State *s)
{
  static const uint64 iv[] = {
      INIT(0x6a09e667, 0xf3bcc908),
      INIT(0xbb67ae85, 0x84caa73b),
      INIT(0x3c6ef372, 0xfe94f82b),
      INIT(0xa54ff53a, 0x5f1d36f1),
      INIT(0x510e527f, 0xade682d1),
      INIT(0x9b05688c, 0x2b3e6c1f),
      INIT(0x1f83d9ab, 0xfb41bd6b),
      INIT(0x5be0cd19, 0x137e2179),
  };
  int i;
  for (i = 0; i < 8; i++)
    s->h[i] = iv[i];
}

static void SHA384_Core_Init(SHA512_State *s)
{
  static const uint64 iv[] = {
      INIT(0xcbbb9d5d, 0xc1059ed8),
      INIT(0x629a292a, 0x367cd507),
      INIT(0x9159015a, 0x3070dd17),
      INIT(0x152fecd8, 0xf70e5939),
      INIT(0x67332667, 0xffc00b31),
      INIT(0x8eb44a87, 0x68581511),
      INIT(0xdb0c2e0d, 0x64f98fa7),
      INIT(0x47b5481d, 0xbefa4fa4),
  };
  int i;
  for (i = 0; i < 8; i++)
    s->h[i] = iv[i];
}

static void SHA512_Block(SHA512_State *s, uint64 *block)
{
  uint64 w[80];
  uint64 a, b, c, d, e, f, g, h;
  static const uint64 k[] = {
      INIT(0x428a2f98, 0xd728ae22), INIT(0x71374491, 0x23ef65cd),
      INIT(0xb5c0fbcf, 0xec4d3b2f), INIT(0xe9b5dba5, 0x8189dbbc),
      INIT(0x3956c25b, 0xf348b538), INIT(0x59f111f1, 0xb605d019),
      INIT(0x923f82a4, 0xaf194f9b), INIT(0xab1c5ed5, 0xda6d8118),
      INIT(0xd807aa98, 0xa3030242), INIT(0x12835b01, 0x45706fbe),
      INIT(0x243185be, 0x4ee4b28c), INIT(0x550c7dc3, 0xd5ffb4e2),
      INIT(0x72be5d74, 0xf27b896f), INIT(0x80deb1fe, 0x3b1696b1),
      INIT(0x9bdc06a7, 0x25c71235), INIT(0xc19bf174, 0xcf692694),
      INIT(0xe49b69c1, 0x9ef14ad2), INIT(0xefbe4786, 0x384f25e3),
      INIT(0x0fc19dc6, 0x8b8cd5b5), INIT(0x240ca1cc, 0x77ac9c65),
      INIT(0x2de92c6f, 0x592b0275), INIT(0x4a7484aa, 0x6ea6e483),
      INIT(0x5cb0a9dc, 0xbd41fbd4), INIT(0x76f988da, 0x831153b5),
      INIT(0x983e5152, 0xee66dfab), INIT(0xa831c66d, 0x2db43210),
      INIT(0xb00327c8, 0x98fb213f), INIT(0xbf597fc7, 0xbeef0ee4),
      INIT(0xc6e00bf3, 0x3da88fc2), INIT(0xd5a79147, 0x930aa725),
      INIT(0x06ca6351, 0xe003826f), INIT(0x14292967, 0x0a0e6e70),
      INIT(0x27b70a85, 0x46d22ffc), INIT(0x2e1b2138, 0x5c26c926),
      INIT(0x4d2c6dfc, 0x5ac42aed), INIT(0x53380d13, 0x9d95b3df),
      INIT(0x650a7354, 0x8baf63de), INIT(0x766a0abb, 0x3c77b2a8),
      INIT(0x81c2c92e, 0x47edaee6), INIT(0x92722c85, 0x1482353b),
      INIT(0xa2bfe8a1, 0x4cf10364), INIT(0xa81a664b, 0xbc423001),
      INIT(0xc24b8b70, 0xd0f89791), INIT(0xc76c51a3, 0x0654be30),
      INIT(0xd192e819, 0xd6ef5218), INIT(0xd6990624, 0x5565a910),
      INIT(0xf40e3585, 0x5771202a), INIT(0x106aa070, 0x32bbd1b8),
      INIT(0x19a4c116, 0xb8d2d0c8), INIT(0x1e376c08, 0x5141ab53),
      INIT(0x2748774c, 0xdf8eeb99), INIT(0x34b0bcb5, 0xe19b48a8),
      INIT(0x391c0cb3, 0xc5c95a63), INIT(0x4ed8aa4a, 0xe3418acb),
      INIT(0x5b9cca4f, 0x7763e373), INIT(0x682e6ff3, 0xd6b2b8a3),
      INIT(0x748f82ee, 0x5defb2fc), INIT(0x78a5636f, 0x43172f60),
      INIT(0x84c87814, 0xa1f0ab72), INIT(0x8cc70208, 0x1a6439ec),
      INIT(0x90befffa, 0x23631e28), INIT(0xa4506ceb, 0xde82bde9),
      INIT(0xbef9a3f7, 0xb2c67915), INIT(0xc67178f2, 0xe372532b),
      INIT(0xca273ece, 0xea26619c), INIT(0xd186b8c7, 0x21c0c207),
      INIT(0xeada7dd6, 0xcde0eb1e), INIT(0xf57d4f7f, 0xee6ed178),
      INIT(0x06f067aa, 0x72176fba), INIT(0x0a637dc5, 0xa2c898a6),
      INIT(0x113f9804, 0xbef90dae), INIT(0x1b710b35, 0x131c471b),
      INIT(0x28db77f5, 0x23047d84), INIT(0x32caab7b, 0x40c72493),
      INIT(0x3c9ebe0a, 0x15c9bebc), INIT(0x431d67c4, 0x9c100d4c),
      INIT(0x4cc5d4be, 0xcb3e42b6), INIT(0x597f299c, 0xfc657e2a),
      INIT(0x5fcb6fab, 0x3ad6faec), INIT(0x6c44198c, 0x4a475817),
  };

  int t;

  for (t = 0; t < 16; t++)
    w[t] = block[t];

  for (t = 16; t < 80; t++) {
    uint64 p, q, r, tmp;
    smallsigma1(p, tmp, w[t - 2]);
    smallsigma0(q, tmp, w[t - 15]);
    add(r, p, q);
    add(p, r, w[t - 7]);
    add(w[t], p, w[t - 16]);
  }

  a = s->h[0];
  b = s->h[1];
  c = s->h[2];
  d = s->h[3];
  e = s->h[4];
  f = s->h[5];
  g = s->h[6];
  h = s->h[7];

  for (t = 0; t < 80; t += 8) {
    uint64 tmp, p, q, r;

#define ROUND(j, a, b, c, d, e, f, g, h)                                       \
  bigsigma1(p, tmp, e);                                                        \
  Ch(q, tmp, e, f, g);                                                         \
  add(r, p, q);                                                                \
  add(p, r, k[j]);                                                             \
  add(q, p, w[j]);                                                             \
  add(r, q, h);                                                                \
  bigsigma0(p, tmp, a);                                                        \
  Maj(tmp, q, a, b, c);                                                        \
  add(q, tmp, p);                                                              \
  add(p, r, d);                                                                \
  d = p;                                                                       \
  add(h, q, r);

    ROUND(t + 0, a, b, c, d, e, f, g, h);
    ROUND(t + 1, h, a, b, c, d, e, f, g);
    ROUND(t + 2, g, h, a, b, c, d, e, f);
    ROUND(t + 3, f, g, h, a, b, c, d, e);
    ROUND(t + 4, e, f, g, h, a, b, c, d);
    ROUND(t + 5, d, e, f, g, h, a, b, c);
    ROUND(t + 6, c, d, e, f, g, h, a, b);
    ROUND(t + 7, b, c, d, e, f, g, h, a);
  }

  {
    uint64 tmp;
#define UPDATE(state, local) (tmp = state, add(state, tmp, local))
    UPDATE(s->h[0], a);
    UPDATE(s->h[1], b);
    UPDATE(s->h[2], c);
    UPDATE(s->h[3], d);
    UPDATE(s->h[4], e);
    UPDATE(s->h[5], f);
    UPDATE(s->h[6], g);
    UPDATE(s->h[7], h);
  }
}

/* ----------------------------------------------------------------------
 * Outer SHA512 algorithm: take an arbitrary length byte string,
 * convert it into 16-doubleword blocks with the prescribed padding
 * at the end, and pass those blocks to the core SHA512 algorithm.
 */

void SHA512_Init(SHA512_State *s)
{
  int i;
  SHA512_Core_Init(s);
  s->blkused = 0;
  for (i = 0; i < 4; i++)
    s->len[i] = 0;
}

void SHA384_Init(SHA512_State *s)
{
  int i;
  SHA384_Core_Init(s);
  s->blkused = 0;
  for (i = 0; i < 4; i++)
    s->len[i] = 0;
}

void SHA512_Bytes(SHA512_State *s, const void *p, int len)
{
  unsigned char *q = (unsigned char *)p;
  uint64 wordblock[16];
  uint32 lenw = len;
  int i;

  /*
   * Update the length field.
   */
  for (i = 0; i < 4; i++) {
    s->len[i] += lenw;
    lenw = (s->len[i] < lenw);
  }

  if (s->blkused && s->blkused + len < BLKSIZE) {
    /*
     * Trivial case: just add to the block.
     */
    memcpy(s->block + s->blkused, q, len);
    s->blkused += len;
  } else {
    /*
     * We must complete and process at least one block.
     */
    while (s->blkused + len >= BLKSIZE) {
      memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused);
      q += BLKSIZE - s->blkused;
      len -= BLKSIZE - s->blkused;
      /* Now process the block. Gather bytes big-endian into words */
      for (i = 0; i < 16; i++) {
        uint32 h, l;
        h = (((uint32)s->block[i * 8 + 0]) << 24) |
            (((uint32)s->block[i * 8 + 1]) << 16) |
            (((uint32)s->block[i * 8 + 2]) << 8) |
            (((uint32)s->block[i * 8 + 3]) << 0);
        l = (((uint32)s->block[i * 8 + 4]) << 24) |
            (((uint32)s->block[i * 8 + 5]) << 16) |
            (((uint32)s->block[i * 8 + 6]) << 8) |
            (((uint32)s->block[i * 8 + 7]) << 0);
        BUILD(wordblock[i], h, l);
      }
      SHA512_Block(s, wordblock);
      s->blkused = 0;
    }
    memcpy(s->block, q, len);
    s->blkused = len;
  }
}

void SHA512_Final(SHA512_State *s, unsigned char *digest)
{
  int i;
  int pad;
  unsigned char c[BLKSIZE];
  uint32 len[4];

  if (s->blkused >= BLKSIZE - 16)
    pad = (BLKSIZE - 16) + BLKSIZE - s->blkused;
  else
    pad = (BLKSIZE - 16) - s->blkused;

  for (i = 4; i--;) {
    uint32 lenhi = s->len[i];
    uint32 lenlo = i > 0 ? s->len[i - 1] : 0;
    len[i] = (lenhi << 3) | (lenlo >> (32 - 3));
  }

  memset(c, 0, pad);
  c[0] = 0x80;
  SHA512_Bytes(s, &c, pad);

  for (i = 0; i < 4; i++) {
    c[i * 4 + 0] = (len[3 - i] >> 24) & 0xFF;
    c[i * 4 + 1] = (len[3 - i] >> 16) & 0xFF;
    c[i * 4 + 2] = (len[3 - i] >> 8) & 0xFF;
    c[i * 4 + 3] = (len[3 - i] >> 0) & 0xFF;
  }

  SHA512_Bytes(s, &c, 16);

  for (i = 0; i < 8; i++) {
    uint32 h, l;
    EXTRACT(h, l, s->h[i]);
    digest[i * 8 + 0] = (h >> 24) & 0xFF;
    digest[i * 8 + 1] = (h >> 16) & 0xFF;
    digest[i * 8 + 2] = (h >> 8) & 0xFF;
    digest[i * 8 + 3] = (h >> 0) & 0xFF;
    digest[i * 8 + 4] = (l >> 24) & 0xFF;
    digest[i * 8 + 5] = (l >> 16) & 0xFF;
    digest[i * 8 + 6] = (l >> 8) & 0xFF;
    digest[i * 8 + 7] = (l >> 0) & 0xFF;
  }
}

void SHA384_Final(SHA512_State *s, unsigned char *digest)
{
  unsigned char biggerDigest[512 / 8];
  SHA512_Final(s, biggerDigest);
  memcpy(digest, biggerDigest, 384 / 8);
}

void SHA512_Simple(const void *p, int len, unsigned char *output)
{
  SHA512_State s;

  SHA512_Init(&s);
  SHA512_Bytes(&s, p, len);
  SHA512_Final(&s, output);
  smemclr(&s, sizeof(s));
}

void SHA384_Simple(const void *p, int len, unsigned char *output)
{
  SHA512_State s;

  SHA384_Init(&s);
  SHA512_Bytes(&s, p, len);
  SHA384_Final(&s, output);
  smemclr(&s, sizeof(s));
}

/*
 * Thin abstraction for things where hashes are pluggable.
 */

static void *sha512_init(void)
{
  SHA512_State *s;

  s = snew(SHA512_State);
  SHA512_Init(s);
  return s;
}

static void *sha512_copy(const void *vold)
{
  const SHA512_State *old = (const SHA512_State *)vold;
  SHA512_State *s;

  s = snew(SHA512_State);
  *s = *old;
  return s;
}

static void sha512_free(void *handle)
{
  SHA512_State *s = handle;

  smemclr(s, sizeof(*s));
  sfree(s);
}

static void sha512_bytes(void *handle, const void *p, int len)
{
  SHA512_State *s = handle;

  SHA512_Bytes(s, p, len);
}

static void sha512_final(void *handle, unsigned char *output)
{
  SHA512_State *s = handle;

  SHA512_Final(s, output);
  sha512_free(s);
}

const struct ssh_hash ssh_sha512 = {sha512_init,
                                    sha512_copy,
                                    sha512_bytes,
                                    sha512_final,
                                    sha512_free,
                                    64,
                                    "SHA-512"};

static void *sha384_init(void)
{
  SHA512_State *s;

  s = snew(SHA512_State);
  SHA384_Init(s);
  return s;
}

static void sha384_final(void *handle, unsigned char *output)
{
  SHA512_State *s = handle;

  SHA384_Final(s, output);
  smemclr(s, sizeof(*s));
  sfree(s);
}

const struct ssh_hash ssh_sha384 = {sha384_init,
                                    sha512_copy,
                                    sha512_bytes,
                                    sha384_final,
                                    sha512_free,
                                    48,
                                    "SHA-384"};

#ifdef TEST

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

int main(void)
{
  unsigned char digest[64];
  int i, j, errors;

  struct {
    const char *teststring;
    unsigned char digest512[64];
  } tests[] = {
      {"abc",
       {
           0xdd, 0xaf, 0x35, 0xa1, 0x93, 0x61, 0x7a, 0xba, 0xcc, 0x41, 0x73,
           0x49, 0xae, 0x20, 0x41, 0x31, 0x12, 0xe6, 0xfa, 0x4e, 0x89, 0xa9,
           0x7e, 0xa2, 0x0a, 0x9e, 0xee, 0xe6, 0x4b, 0x55, 0xd3, 0x9a, 0x21,
           0x92, 0x99, 0x2a, 0x27, 0x4f, 0xc1, 0xa8, 0x36, 0xba, 0x3c, 0x23,
           0xa3, 0xfe, 0xeb, 0xbd, 0x45, 0x4d, 0x44, 0x23, 0x64, 0x3c, 0xe8,
           0x0e, 0x2a, 0x9a, 0xc9, 0x4f, 0xa5, 0x4c, 0xa4, 0x9f,
       }},
      {"abcdefghbcdefghicdefghijdefghijkefghijklfghijklmghijklmn"
       "hijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu",
       {
           0x8e, 0x95, 0x9b, 0x75, 0xda, 0xe3, 0x13, 0xda, 0x8c, 0xf4, 0xf7,
           0x28, 0x14, 0xfc, 0x14, 0x3f, 0x8f, 0x77, 0x79, 0xc6, 0xeb, 0x9f,
           0x7f, 0xa1, 0x72, 0x99, 0xae, 0xad, 0xb6, 0x88, 0x90, 0x18, 0x50,
           0x1d, 0x28, 0x9e, 0x49, 0x00, 0xf7, 0xe4, 0x33, 0x1b, 0x99, 0xde,
           0xc4, 0xb5, 0x43, 0x3a, 0xc7, 0xd3, 0x29, 0xee, 0xb6, 0xdd, 0x26,
           0x54, 0x5e, 0x96, 0xe5, 0x5b, 0x87, 0x4b, 0xe9, 0x09,
       }},
      {NULL,
       {
           0xe7, 0x18, 0x48, 0x3d, 0x0c, 0xe7, 0x69, 0x64, 0x4e, 0x2e, 0x42,
           0xc7, 0xbc, 0x15, 0xb4, 0x63, 0x8e, 0x1f, 0x98, 0xb1, 0x3b, 0x20,
           0x44, 0x28, 0x56, 0x32, 0xa8, 0x03, 0xaf, 0xa9, 0x73, 0xeb, 0xde,
           0x0f, 0xf2, 0x44, 0x87, 0x7e, 0xa6, 0x0a, 0x4c, 0xb0, 0x43, 0x2c,
           0xe5, 0x77, 0xc3, 0x1b, 0xeb, 0x00, 0x9c, 0x5c, 0x2c, 0x49, 0xaa,
           0x2e, 0x4e, 0xad, 0xb2, 0x17, 0xad, 0x8c, 0xc0, 0x9b,
       }},
  };

  errors = 0;

  for (i = 0; i < sizeof(tests) / sizeof(*tests); i++) {
    if (tests[i].teststring) {
      SHA512_Simple(tests[i].teststring, strlen(tests[i].teststring), digest);
    } else {
      SHA512_State s;
      int n;
      SHA512_Init(&s);
      for (n = 0; n < 1000000 / 40; n++)
        SHA512_Bytes(&s, "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", 40);
      SHA512_Final(&s, digest);
    }
    for (j = 0; j < 64; j++) {
      if (digest[j] != tests[i].digest512[j]) {
        fprintf(stderr,
                "\"%s\" digest512 byte %d should be 0x%02x, is 0x%02x\n",
                tests[i].teststring,
                j,
                tests[i].digest512[j],
                digest[j]);
        errors++;
      }
    }
  }

  printf("%d errors\n", errors);

  return 0;
}

#endif
